WASHINGTON - Over and over in the health-care debate, President Obama said people who liked their current coverage would be able to keep it.

But an early draft of an administration regulation estimates that many employers will be forced to make changes to their health plans under the new law. In just three years, a majority of workers - 51 percent - will be in plans subject to new federal requirements, according to the draft.

The types of changes that employers would be forced to make include offering preventive care without co-payments and instituting an appeals process for disputed claims that follows new federal guidelines. The law already requires all health plans to extend coverage to young adult children until they turn 26. But such changes also nudge costs up.

The Obama administration said the draft regulation was an early version undergoing revision. Nonetheless, the leaked document was drawing widespread interest Friday from lobbying firms that represent employers and insurance companies and on Capitol Hill.

"What we are getting here is a clear indication that most plans will have to change," said James Gelfand, health-policy director for the U.S. Chamber of Commerce. "From an employer's point of view, that's a bad thing. These changes, whether or not they're good for consumers, are most certainly accompanied by a cost."

An administration official, speaking on condition of anonymity because the rules were still being written, said the final version would uphold Obama's promise, accommodating employers' desire for flexibility while protecting consumers from runaway costs.

Employer-provided coverage is the mainstay of the nation's health-insurance system and is expected to remain so even after the new health-care law is fully phased in.

The main issue in the 83-page regulation is how to deal with what the government calls "grandfathered" health plans.

Those are plans that predated the health-care law and are exempt from many, but not all, of its consumer protections. Lawmakers created the special category to deliver on Obama's promise that people can keep the coverage they have if they like it.

But health plans change frequently. Premiums and co-payments keep rising. Coverage is expanded for some services and restricted for others. Lawmakers asked regulators to spell out how much an employer can change a plan and still claim it to be grandfathered, exempting it from closer federal regulation.

Employers say the draft rules are too inflexible. Generally, plans can lose their protected status by increasing copayments and deductibles above certain limits. Gelfand, of the Chamber of Commerce, said medical inflation alone would push many employers over the line.